ES2316652T3 - PROCEDURE FOR HYDROFORMILATION OF OLEFINS, CATALYZED BY RHODIUM, MEASURING REDUCTION OF LOSSES OF RHODIUM. - Google Patents

Abstract

Process for preparing aldehydes and alcohols by rhodium-catalyzed hydroformylation of olefins having 6-20 carbon atoms with subsequent separation by distillation of the output from the hydroformylation reaction into the hydroformylation products and a rhodium-containing solution and recirculation of this solution to the hydroformylation reaction, wherein the rhodium concentration of the recirculated rhodium-containing solution is 20-150 ppm by mass.

Description

Procedure for hydroformylation of olefins, catalyzed by rhodium, mediating loss reduction Rhodium

The present invention relates to a procedure for the preparation of aldehydes and alcohols by a hydroformylation of olefins, catalyzed by rhodium, being minimized losses of active rhodium catalyst that result by treating the discharge fraction of the hydroformylation reaction.

At the technical scale, aldehydes and / or are prepared alcohols by hydroformylation of olefins with catalysts of cobalt or rhodium. In such a case, most of the time it is advantageous the use of rhodium catalysts, since with they can achieve selectivities and yields of higher products. Compared to cobalt, rhodium, however, it is more expensive, so in the case of the hydroformylation of olefins to give the corresponding aldehydes with rhodium catalysts, the catalyst constitutes a non-negligible factor of costs. In order to raise the profitability, therefore, consumption should be reduced catalyst specific. By such concept, the amount of the catalyst, which must be contributed to the process in the case of long-term operation, in order to guarantee a constant activity level of the catalyst.

The reaction of olefins, catalyzed by rhodium, to give the corresponding aldehydes, it is done in the largest part of the cases in a homogeneous liquid phase. In the case of hydroformylations in a homogeneous phase, that is to say that the catalyst, olefins, products, solvents, etc., are present in the same phase, the problem of separating the catalyst after the reaction from the discharge fraction of the reaction. This can be done in a simple way by distillation separation of the starting compounds (educts) they have not reacted and the products; the catalyst that found in the tail part (bottom of the reactor), which it is dissolved in most cases in high components boiling point, it is then recycled to the reactor. In that In this case, distillation can be carried out continuously or discontinuous

In the case of distillation separation of rhodium catalyst, you can check frequently a decomposition or deactivation of the catalyst. Especially in the case of the hydroformylation of longer chain olefins, the distillation, because of the high boiling points of products, can only be carried out at one high temperature and / or at a reduced pressure, that is to say necessary conditions for catalyst separation favor upon deactivation

In order to decrease the deactivation of the catalyst during the treatment of the discharge fraction from the reactor in the case of olefin hydroformylation reactions, Rhodium catalyzed, several procedures are known:

In European patent document EP 0272608, describes a process, in which a catalyst of Rhodium with triphenyl phosphine oxide ligands. In the case of the treatment of the reaction discharge fraction, before distillation, triphenyl phosphine is added (in the amount nine times greater than rhodium). The residue of distillation therefore contains rhodium complexes with triphenyl phosphine as a ligand, as well as triphenyl phosphine and oxide triphenyl phosphine. Then the amount of total triphenyl phosphine, ie the free and the converted into complexes, it oxidizes to give triphenyl phosphine, and this catalyst solution It is recycled to the reactor. For the oxidation of the Triphenyl phosphine is used oxygen or a peroxide. Other variants of this method are described in the documents of Japanese patents JP 63,222,139, JP 63,208,540, German patent DE 3,338,340 and JP 63,218,640.

These procedures have the disadvantage that triphenyl phosphine is constantly consumed. Starting from this results in oxidation the equivalent amount of oxide of triphenyl phosphine. In order to limit your concentration in the liquid with catalyst or respectively in the reactor, a discharged current is needed, by which Remove rhodium again. Additionally you need a device oxidation. In the case of oxidation, when not used precisely air, certain costs result for the agent of oxidation.

In order to stabilize the ligands that contain rhodium phosphorus, other compounds can be added to the hydroformylation reaction and / or the treatment stage of the reaction products.

In US patent documents US 5,731,472, US 5,767,321 and EP 0.149,894 describe some procedures for hydroformylation of n-butenos. They use catalysts with rhodium, which contain phosphite ligands and that stabilize by an addition of amines. It is disadvantageous in this case the fact that amines can act as catalysts for aldol condensations, and therefore the formation of high boiling compounds.

Hydroformylation of a mixture of olefins from C 8, prepared by dimerization of butenes, mediating the catalysis by complex compounds of rhodium and its stabilization with substituted phenols, described in JP 04-164042. In this case, the rhodium compound, the ligand and stabilizer are used in the molar ratio of 10/1/50 Disadvantages in the case of these procedures are costs for the stabilizer and the expense for its separation.

Usually, rhodium catalyst is recovered in the form of a solution in a high point solvent of boiling, by moderate distillation of the discharge fraction of the hydroformylation reaction.

In the case of the hydroformylation of olefins in presence of rhodium catalysts, result with frequencies small amounts of high boiling compounds such as secondary products High boiling compounds they are products of aldolization and acetalization as well as - disproportionation of aldehydes to give acids and alcohols - esters of these acids. These high point compounds of boiling remain, when distilling the fraction of discharge of hydroformylation, together with rhodium compounds in the tail part of the distillation. So, in a Continuous procedure, the concentration of high compounds boiling point in the hydroformylation reactor can be keep at a constant value, in an almost stationary state it it must separate precisely so many high compounds boiling point, such as that formed in the reaction of hydroformylation This is done by deliberate download of a part of the tail fraction of the distillation. Together with current discharged, partial quantities of the Active rhodium catalyst from the process circuit. At ideal case the amount discharged from rhodium would correspond precisely to the amount of rhodium that should be added dosed at a later time, in the case of a continuous procedure, for the maintenance of a state stationary.

In the cases of usual procedures, you must add later, however, a greater amount of Rhodium, since during the distillation treatment they result, among other reasons because of the thermal solicitation, some insoluble rhodium compounds, such as eg rhodium compounds multinuclear in the form of clusters (in English cluster) and / or rhodium metal. These amounts of rhodium are still present certainly on the team, but they are catalytically inactive and not are available as a catalyst in the reactor of hydroformylation In addition to this, dissolved rhodium compounds, contained in the product of distillation tails, which recycle to the hydroformylation reactor, are less active than a new contribution rhodium catalyst, so that even in the case of the same concentration of rhodium in the reactor of hydroformylation with recycled rhodium compounds, a Less space and time performance.

The profitability of a procedure hydroformylation with rhodium catalysts therefore depends mainly of the specific consumption of rhodium. I subsisted so both the mission of developing a procedure for preparation of aldehydes by a hydroformylation of olefins, catalyzed by rhodium, distinguished by a small consumption of catalyst and that can be carried out without the addition of substances that stabilize to the catalyst.

Surprisingly, it was found that consumption of catalyst of an olefin hydroformylation process, Rhodium catalyzed, can be greatly reduced, when in the case of distillation treatment of the discharge fraction of hydroformylation does not exceed certain concentrations of Rhodium in the tail part of the distillation.

It is therefore object of the present invention a procedure for the preparation of aldehydes and alcohols by a hydroformylation of olefins with 6-20 atoms of carbon, rhodium catalyzed, with subsequent separation by distillation of the discharge fraction of the reaction of hydroformylation, in hydroformylation products and in a solution containing rhodium, and by recycling this solution to the hydroformylation reaction, being 20-150 ppm (parts per million) by mass the rhodium concentration of the Recycled solution containing rhodium.

Preferably, the rhodium concentration of the recycled solution containing rhodium is 20-100 and in particular 20-50 ppm in rhodium mass.

For the execution of the procedure according to invention several variants are possible:

Figure 1 should explain in greater detail a variant of the process according to the invention. Here through from conduit 1 an olefin and a synthesis gas are conducted as well as a solution of catalyst inside the hydroformylation reactor 3. Through the conduction 4 the hydroformylation discharge fraction is incorporated in the distillation separation stage 5, where as product of heads 6 the aldehydes and alcohols that are separated are separated wish. The queue product 7 contains the rhodium catalyst, and / or high boiling compounds, and / or aldehydes and non-separated alcohols, and / or inert solvents. Optionally, a part of the solution containing rhodium must be downloaded to through conduction 8. The solution is recycled to reactor 3, being able to add, through 9, catalyst again input.

As solvents, the solution with a content Rhodium contains the reaction products of the reaction of hydroformylation, ie aldehydes, alcohols and the compounds of high boiling point that have formed, and inert solvents added, selected from texanol, dioctyl phthalate (PDO) or Diisononyl Phthalate (DINP). Rhodium concentration is adjusted by distillation separation of the fraction discharge of the hydroformylation reaction, namely by corresponding proportion of alcohols and aldehydes. The amount of the queue product can be adjusted using a mode of corresponding operation of distillation equipment (temperature, pressure). The solvents used are the compounds high boiling point formed by the reaction and the inert solvents added, in each case alone or additionally with the alcohols and aldehydes that have formed through the reaction.

The starting compounds for the process according to the invention are olefins or mixtures of olefins with 6 to 20 carbon atoms as well as with double C-C bonds located at the ends and / or inside. The mixtures can be make up olefins with an equal, similar number of C atoms (± 2) or manifestly different (> ± 2). How olefins, which can be used either in pure form, in a mixture of isomers or in a mixture with other olefins with a number other than C atoms as starting compounds, they must be mention for example: 1-, 2- or 3-hexene, 1-heptene, double-bond linear heptenes located inside (2-heptene, 3-heptene, etc.), mixtures of linear heptenes, 2- or 3-methyl-1-hexene, 1-octene, linear octenes with a double bond located inside, mixtures of linear octenes, 2- or 3-methyl-heptene, 1-noneno, linear nonenos with a double bond located inside, mixtures of linear nonenos, 2-, 3- or 4-methyl-octenes, 1-, 2-, 3-, 4- or 5-dean, 2-ethyl-1-octene, 1-dodecene, linear dodecens with a double bond located inside, mixtures of linear dodecenes, 1-tetradecene, linear tetradecenes with a double link located inside, mixtures of linear tetradecenes, 1-hexadecene, linear hexadecenes with a double link located inside, mixtures of linear hexadecenes. Appropriate starting compounds are, inter alia, the mixture of isomeric hexenes that results in the case of dimerization of propene (dipropene), the mixture of isomeric octenes that results in the case of the dimerization of butenes (dye), the mixture of nonenos isomers resulting in the case of trimerization of propene (tripropene), the mixture of isomeric dodecenes that results in the case of tetramerization of propene or trimerization of butenes (tetrapropene or tributene), the hexadecene mixture that results in the case of tetramerization of butenes (tetrabutene) as well as mixtures of olefins that are prepared by concomitant oligomerization of olefins that have a diverse number of C atoms (preferably 2 to 4), if any after distillation separation in fractions that have a number of equal or similar C atoms (± 2). Also I know they can use olefins or mixtures of olefins, which have been produced by a synthesis of Fischer-Tropsch. In addition to this, you can use some olefins, which have been prepared by olefin metathesis or by other technical processes. Preferred starting compounds are mixtures of octenes, nonenos, dodecenes or isomeric hexadecenes, that is, olefin oligomers lower, such as n-butenes, isobutene or propene Other starting compounds, also well suited, are C5 olefin oligomers.

In the process according to the invention, certain modified rhodium complex compounds can be used as catalysts. These rhodium catalysts can be incorporated into the process in the form of their active complex compounds, but technically it is generally easier to generate the catalysts in situ from stable rhodium compounds, easily stored. Rhodium compounds, suitable for this, are for example rhodium (II) and rhodium (III) salts, such as rhodium (III) chloride, rhodium (III) nitrate, rhodium (III) sulfate, potassium sulfate and rhodium, a rhodium (II) or respectively rhodium (III) carboxylate, rhodium (II) and rhodium (III) acetates, rhodium (II) octanoate, rhodium (II) nonanoate, rhodium oxide (III), salts of rhodium (III) acid [rhodium (III)] and tris-ammonium hexachloroxylate. In addition, certain complex rhodium compounds such as rhodium biscarbonyl-acetylacetonate and acetylacetonate-bis-ethylene-rhodium (I) are suitable. Rhodium acetate, rhodium octanoate and rhodium nonanoate are especially suitable.

Usually approximately 1 to 500 and preferably 3 to 50 moles of a ligand for each rhodium mole Newly added ligand can be added in any moment of the reaction, in order to keep constant free ligand concentration.

In the process according to the invention, the Rhodium concentration in the hydroformylation reactor is preferably 1 to 50 ppm by mass, in particular 5 to 25 ppm mass.

The choice of added ligands is not restricted in the process according to the invention, but It depends on the olefin used and the desired products. Ligands Preferred are ligands containing nitrogen atoms, phosphorus, arsenic or antimony; Especially preferred are phosphorus ligands. The ligands can be monodentate or multidentado, in the case of chiral ligands can be used both the racemate and also an enantiomer or diastereoisomer. It is also possible to use a mixture of two or more different ligands Phosphorus ligands use in particular those that they form rhodium complex compounds less stable than triphenyl phosphine, such as for example oxides of phosphines, phosphites, phosphonites and phosphites.

Examples of phosphites are trimethyl phosphite, triethyl phosphite, phosphite tri-n-propyl phosphite tri-i-propyl phosphite tri-n-butyl phosphite tri-i-butyl phosphite tri-t-butyl phosphite tris (2-ethyl-hexyl), phosphite of triphenyl phosphite tris (2,4-di-t-butyl-phenyl), phosphite of tris (2-t-butyl-4-methoxy-phenyl),  phosphite of tris (2-t-butyl-4-methyl-phenyl) and tris (p-cresyl) phosphite. Also I know employ sterically hindered phosphite ligands, such as which result, among others, in documents EP 155.508, US 4,668,651, US 4,748,261, US 4,769,498, US 4,774,361, US 4,835,299, US 4,885,401, US 5,059,710, US 5,113,022, US 5,179,055, US 5,260,491, US 5,264,616, US 5,288,918, US 5,360,938, EP 472,071, EP 518.241 and in the international patent application document WO 97/20795. Triphenyl phosphites are preferably used substituted in each case with 1 or 2 isopropyl groups and / or tert-butyl next to the phenyl rings, preferably in ortho position with respect to phosphite ester grouping.

Examples of phosphonites are methyl diethoxy phosphine, phenyl dimethoxy phosphine, phenyl dimethoxy phosphine, phenyl diphenoxy phosphine, 6-phenoxy-6H-dibenzo [c, e] [1,2] oxa-phosphorin and its derivatives, in which the hydrogen atoms are totally or partially replaced by alkyl or aryl radicals or by halogen atoms, and ligands described in the WO 9843935, JP 09-268152 and DE 198.10.794 and in the German patent application documents DE 199.54.721 and DE 199.54. 510

Common phosphinite ligands are described, among others, in US 5,710,344, WO 95 06627, US 5,360,938 and JP 07082281. Examples thereof are diphenyl- (phenoxy) phosphine and its derivatives, in which hydrogen atoms are totally or partially replaced by alkyl or aryl radicals or halogen atoms, diphenyl (methoxy) phosphine, diphenyl (ethoxy) phosphine, etc.

In the process according to the invention, the rhodium catalyzed hydroformylations are carried out at about pressures of 15 to 300 bars, preferably at pressures of 15 to 270 bars, in particular at pressures of 150-270 bars. The pressure used depends on the structure of the olefins used, of the rhodium catalyst used and the effect wanted. Thus, for example, some can be reacted α-olefins at pressures located by below 64 bars, with high yields of space and time, to give the corresponding aldehydes. In the case of olefins with double bonds located inside, particularly in the cases of branched olefins, are convenient on the contrary higher pressures.

Temperatures for hydroformylations catalyzed by rhodium, according to the invention, are located so generally in the range of 40 ° C to 180 ° C, preferably 90 ° C at 160 ° C, in particular from 130 to 160 ° C.

After hydroformylation, most of the synthesis gas is removed by decompression. From the liquid fraction of reaction discharge, the catalyst is Separate by distillation. The catalyst and ligands, stabilizers, etc., which eventually have been added, remain in the distillation residue or as such residue. By putting in march, or when only a small amount of high boiling compounds, it may be advantageous to employ an inert solvent of high boiling point (which boils at temperatures higher than that of products and compounds of heading), in which the catalyst dissolves. Catalyst dissolved in the high boiling solvent can be transport and recycle then directly to the reactors. Is especially advantageous to use as a high point solvent boiling high boiling side products that They have been trained in the process. Other suitable solvents are high boiling esters, such as monoisobutyrate from 2,2,4-trimethyl-pentanediol-1,3, which is in commerce as texanol.

For the realization on a technical scale of the distillation separation of the catalyst, are applicable Different modes of procedure. Separation of the catalyst solution through evaporating devices falling film, short distance or thin layer stretch, or combinations of these devices. The advantage of one such combinations can be found for example in the fact of separating, in a first stage, the synthesis gas still dissolved as well as a part of the products and starting olefins still present (for example, in a film evaporator descending), for later, in a second stage (for example in a thin layer evaporator), carry out the final separation of the catalyst.

Distillation pressures are located between 5 mbar and 1 bar, preferably between 10 mbar and 100 mbar. Distillation temperatures are 40 to 180 ° C, in particular of 80 to 150 ° C.

Optionally, the solution containing rhodium (tail product) can be further stabilized with carbon monoxide, as described in DE 100 48 301.1.

A part of the solution containing rhodium (product of queues) can be downloaded from the system to keep constant the concentration of high point compounds of boiling in the hydroformylation reactor. The other part of Tail product is recycled to the hydroformylation reactor. With the discharged current is removed from the process also a part of the catalyst (rhodium and ligand). These amounts and others missing amounts of rhodium and ligand in the recycled stream, must be added dosed in order to maintain a certain concentration of the catalyst in the reactor of hydroformylation In the ideal case, they should only be Replace these amounts of rhodium catalyst.

Optionally, from the current discharged can be separated, for example by distillation, others additional products

From the discharged current you can recover rhodium according to known procedures.

Vapors, which result from increasing concentration, can be distilled off in the products Wanted (targets), aldehydes and alcohols, hydrocarbons and others secondary products From the hydrocarbon fraction, they can eventually obtain olefins, which can be recycled to process.

The aldehydes obtained by process according to the invention, can be used as such, for example as an odoriferous substance, they can be oxidized to give carboxylic acids or can be hydrogenated to give alcohols.

The alcohols resulting in the procedure according to the invention, or the alcohols obtained by hydrogenation of aldehydes are precursor compounds for esters, in particular plasticizing agents, such as, for example, phthalates, hydrophthalates, adipates, citrates, trimellitatos, and for detergents. In addition, they can be used as solvents

The following Examples should explain the invention, without restricting its scope of application, which is established from the specification and the claims of this patent.

Example 1 Oxygenation, catalyzed by rhodium, of a C12 olefin (tributene) with new contribution catalyst

In an autoclave with a capacity of 10 l, 5,000 g of a tributene from the Octol process were reacted at 135 ° C, under a synthesis gas pressure of 250 bar for 4 hours, in the presence of a modified rhodium catalyst with a phosphite. The active rhodium catalyst was generated in situ from rhodium octanoate and tris phosphite (2,4-di-tert-butyl-phenyl).

Rhodium concentration (referred to mass total reaction) was adjusted to 10 ppm; phosphorus molar ratio Rhodium (P / Rh) was 10 to 1.

As a high point inert solvent of boiling, 250 g of texanol was added to the reaction mixture (monoisobutyrate of 2,2,4-trimethyl-pentanediol-1,3).

The degree of olefin conversion was monitored both through a GC analysis (from Gas Chromatography = gas chromatography), as well as the amount of gas of synthesis that had been collected. After 4 hours it was interrupted the reaction.

The reaction discharge fraction contained 16.5% by mass of a C12 olefin, 78.1% by mass of an aldehyde of C13 (iso-tridecanal), 4.3% by mass of an alcohol of C13 (iso-tridecanol) and 1.1% by mass of compounds  high boiling point. This product composition corresponds to a degree of conversion of the tributene of 81.2% and a yield of valuable products (C13 aldehydes / alcohols) of 79.7%

Example 2

Example comparative

Rhodium recovery from the discharge fraction of the reaction

For catalyst recovery, 2,500 g of the reaction discharge fraction, from Example 1, separated in a laboratory thin layer evaporator at 130 ° C and 20 mbar. In such a case, the high point compound of boil, which contained rhodium, was separated from the low compounds boiling point (valuable products and C13 olefin that does not had reacted). Under the selected separation conditions,  was obtained in the queue part of the layer evaporator apparatus thin a high boiling compound containing rhodium (tail discharge fraction) with a rhodium content of 248 ppm.

Example 3

According to invention

Rhodium recovery from the discharge fraction of the reaction

As in Example 2, for the recovery of 2,500 g of the discharge fraction of the catalyst were used reaction from Example 1, in a layer evaporator laboratory thin, at 130ºC and 40 mbar. In this case, the high boiling compound, which contained rhodium, separated of low boiling compounds (valuable products, and the C13 olefin that had not reacted). In the conditions chosen separation, softer compared to those of Example 2, was achieved in the discharge fraction of the part of glues a rhodium content of 43 ppm.

Example 4

Example of comparison

Oxygenation of a C12 olefin (tributene) with catalyst recycling

In an autoclave with a capacity of 2 l, they reacted 1,000 g of a tributene from the process Octol at 135 ° C, under a synthesis gas pressure of 250 bar, for 4 hours in the presence of a rhodium catalyst, consumed and recycled The catalyst precursor compound was used as high boiling compound containing rhodium, highly concentrated, with 248 ppm rhodium, which had been obtained in the Example 2. In this case the rhodium content (referred to the mass of total reaction) was adjusted to 10 ppm, as in Example 1. The Molar ratio of phosphorus to rhodium (P / Rh) was 10 to 1.

The degree of olefin conversion was monitored both by GC analysis and also by the amount of synthesis gas collected. After a test time period of 4 hours, a conversion rate of 67.3% tribute and a yield of valuable products (aldehyde / C13 alcohol) of 66.2% were determined. In comparison with the new contribution rhodium catalyst (Example 1), in the case of the use of the consumed catalyst
I can see a clear reversal of the degree of conversion and the performance of valuable products.

Example 5

According to invention

Oxygenation of a C12 olefin (tributene) with a catalyst

In an autoclave with a capacity of 2 l, they reacted 1,000 g of a tributene from the process Octol at 135 ° C under a synthesis gas pressure of 250 bar for 4 hours, in the presence of a rhodium catalyst, consumed and recycled The catalyst precursor compound was used as high boiling compound with rhodium content, with 43 ppm rhodium, from Example 3, which was little concentrated compared to Example 2. Rhodium content (referred to total mass) was adjusted to 10 ppm as in the Examples 1 and 4. The ratio of phosphorus to rhodium (P / Rh) was 10 to one.

The degree of olefin conversion was monitored as in Examples 1 and 3, both by GC analysis and also through the amount of synthesis gas collected. After a test period of 4 hours, determined a degree of conversion of the tributene of 80.5% and a yield of valuable products (aldehyde / C13 alcohol) of 79.0% In comparison with the new contribution catalyst (Example 1), in the case of the use of the catalyst consumed, prepared from high boiling compounds with a Rhodium content, less concentrated, with 43 ppm Rh, is not you can check any mention of the degree of Conversion or performance of valuable products.

Claims (3)

1. Procedure for the preparation of aldehydes and alcohols by hydroformylation of olefins with 6-20 carbon atoms, catalyzed by rhodium, with a subsequent distillation separation of the fraction of discharge of the hydroformylation reaction in the products of hydroformylation and in a solution containing rhodium, and by recycling of this solution to the reaction of hydroformylation, characterized because rhodium concentration of the solution Recycled with a rhodium content is 20-150 ppm en masse, realizing that the solution with a rhodium content contains as solvents high boiling compounds  formed by the hydroformylation reaction, aldehydes and alcohols, and an inert solvent, selected from texanol, dioctyl phthalate or diisononyl phthalate, and that concentration Rhodium is adjusted by the proportion of aldehydes and alcohols, through distillation separation of the fraction of discharge of the hydroformylation reaction. 2. Procedure in accordance with the claim 1, characterized because rhodium catalysts contain ligands of phosphite. 3. Procedure in accordance with the claim 1 or 2, characterized because rhodium catalysts contain phosphite of tris (2,4-di-t-butyl-phenyl) as a ligand.